Wireless microphone and/or in-ear monitoring system and method of controlling a wireless microphone and/or in-ear monitoring system

Abstract

A wireless microphone and / or in-ear monitoring system having at least one first mobile device for wirelessly transmitting first audio signals. The system also has at least one base station for wirelessly receiving the first audio signals transmitted by the mobile device. The wireless transmission is based on an orthogonal frequency-division multiplexing transmission (OFDM) during a time-division multiple access (TDMA) time slot. Each wireless microphone occupies at least one slot within 2 ms. Each of the TDMA frames has a plurality of slots which respectively have precisely one OFDM symbol. Accordingly, precisely one OFDM symbol is transmitted in each TDMA slot. During a time slot made available in accordance with the TDMA, a transmission is effected on the basis of an OFDM method. The TDMA frame length is so short as a latency of <4 ms is required for professional audio transmission, for example in the case of wireless microphone systems.

Description

[0001]The present application claims priority from International Patent Application No. PCT / EP2016 / 063640 filed on Jun. 14, 2016, which claims priority from German Patent Application No. 10 2015 210 873.2 filed on Jun. 15, 2015, the disclosures of which are incorporated herein by reference in their entirety.FIELD OF THE INVENTION[0002]It is noted that citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.[0003]The present invention concerns a wireless microphone and / or in-ear monitoring system and a method of controlling a wireless microphone and / or in-ear monitoring system.[0004]Professional microphone and in-ear monitoring systems were hitherto unidirectional transmission links which continuously transmit and receive in a narrow channel. As a result the transmission direction was predetermined for each device and bidirectional exchange of items of control information was not possible...

AI Technical Summary

Benefits of technology

[0015]According to a further aspect of the present invention a frame has a plurality of slots for the first audio signal and a plurality of slots for the second audio signal (that is to say channel bundling). Channel bundling serves to enhance robustness and / or quality.

[0022]In the case of OFDM a large number of parallel narrow-band subcarriers is used to transmit information, instead of a single wide-band carrier. The respective carriers are modulated with a low data rate. By virtue of the fact that the signals are in orthogonal relationship with each other, no interference phenomena occur. The advantage of OFDM is that it represents robust transmission in regard to possible multi-path propagation.

[0023]The operation of wireless microphone and in-ear monitoring systems in large halls represents a typical use scenario. There, a large number of propagation paths between transmitting and receiving antennae occur by virtue of reflections at walls, ceilings and at the floor. It is possible to effectively and efficiently counteract the resulting distortions of the reception signal through the channel with the OFDM transmission technology. As a result operational reliability is greatly enhanced in comparison with usual single-carrier systems.

[0026]According to the invention that conflict in aims is resolved by the described comparison information not being individually inserted in each time slot but transmitted jointly as part of a frame for all participating modules. By virtue of that measure it is now possible to provide only precisely one OFDM symbol in a time slot. That affords effective utilization of the time slots with at the same time minimization of the size of the data block which is transmitted in a time slot and thus minimization of the time elapsing from the detection of an audio sample to the transmission thereof.

Problems solved by technology

As a result the transmission direction was predetermined for each device and bidirectional exchange of items of control information was not possible.

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